This invention relates to a means of converting solar energy to mechanical energy. More particularly, it relates to a device which utilizes the rays of the sun to pump fluid into a high pressure accumulator. Such pressurized fluid is useful in performing such mechanical functions as operating hydraulic motors.
In U.S. Pat. No. 3,259,070, description is made of a pump which comprises a thermal-activated piston assembly and a positive displacement fluid chamber. In this device, a thermal motor containing a wax pellet is electrically heated, causing the wax to increase in volume, resulting in the extension of the shaft of the motor. The extended motor shaft actuates the aforementioned piston assembly, resulting in the increase in pressure of the fluid within the fluid chamber. At a predetermined pressure, a valve in the fluid chamber opens permitting the fluid to rapidly discharge into an associated metering system. The supply of electricity to the thermal motor is then cut off by means of a switching device, resulting in the cooling and subsequent shrinking of the wax pellet, allowing the piston assembly and the thermal motor shaft to be retracted via a series of springs. While retracting, the piston chamber is refilled with fluid and the switching device is reset, enabling the electrical energy to be resumed at any time thereafter, starting another cycle of operation.
The device in the above referenced patent is rather complicated in construction, relying on a number of springs to return the piston and thermal motor shaft to be retracted position at the completion of the pumping operation. Another disadvantage of this design is its continued dependence on electrical energy to actuate the thermal motor.
A pumping device, which is not dependent on electrical energy, is disclosed in U.S. Pat. No. 2,688,922 to Bonaventura et al. In this patent, description is made of a hyperbolic reflector, concentrating the sun's rays on one of a plurality of boilers containing liquid. The boiler in the focus of the reflector increases in temperature and pressure causing the contents to be expelled through a check value into an outlet manifold. The resulting decrease in weight causes the empty boiler to be rotated out of the heating zone, being replaced by a heavier, liquid-filled boiler. Being removed from the focused rays of the sun, the empty boiler cools, resulting in the creation of a partial vacuum within. The vacuum draws liquid into the boiler from an inlet manifold through a check valve, preparing the boiler for subsequent heating.
This device is inefficient since a considerable amount of time is required to bring the liquid within the boilers to a point where the boiler's internal pressure is greater than the pressure in the outlet manifold, causing liquid to be evacuated therefrom. A considerable time is likewise required to cool the boiler down to a point where the vacuum created is able to draw liquid from the inlet manifold. This device is also inefficient in that any malfunctions within the boiler would result in considerable down-time while repairs are being made.
Accordingly, it is an object of the present invention to provide a means of producing mechanical energy using solar rays, relying on an external power source only during the initial minutes of operation.
It is another object of this invention to provide a means of producing mechanical energy which operates continuously.
It is further object of the present invention to provide a means of producing mechanical energy which is relatively simple in both construction and operation.
It is still a further object of the present invention to provide a means of producing mechanical energy which has a minimum response time.
It is yet a further object of the present invention to provide a means of producing mechanical energy in which damaged parts can be replaced easily, thus minimizing down-time.
Other objects and advantages of the invention will be apparent from the concluding portion of the specification.